VPSA, or Vacuum Pressure Swing Absorption, is a cutting-edge technology used in oxygen production equipment. Its core function is to separate nitrogen and moisture from oxygen components in the air, and efficiently produce oxygen-rich gas with a purity of 80% – 94%. Compared with other oxygen extraction methods, VPSA performs particularly well in processing large air flows and is an ideal choice for industries with high oxygen demand.
The principle of VPSA oxygen generators to extract oxygen from ambient air is to selectively adsorb nitrogen-rich air in the air to produce a pure oxygen gas flow to meet the needs of various industrial applications.
VPSA oxygen generator products form Fullcryo
The oxygen production capacity ranges from 200Nm³/h to 6500Nm³/h, and the oxygen purity is 80%-94%;
Forming a series of products with different flow rates, pressures and purities.
| Model | FHOX-200 | FHOX-500 | FHOX-1100 | FHOX-2150 | FHOX-4500 | FHOX-6500 | |
| Oxygen flow rate
(90% purity conversion) |
Nm³/h | 200 | 500 | 1100 | 2150 | 4500 | 6500 |
| Product purity
(maximum) |
% | 94 | 94 | 94 | 94 | 94 | 94 |
| Total power of process motor | kW | 132 | 250 | 560 | 1000 | 1800 | 2500 |
| Voltage | kV | 380V | 6kV/10kV | 6kV/10kV | 6kV/10kV | 6kV/10kV | 6kV/10kV |
| Layout | m*m | 15*10 | 20*10 | 20*10 | 25*15 | 30*25 | 40*25 |
| General layout | m*m | 25*15 | 25*20 | 25*20 | 30*30 |
40*30
|
40*40 |
The operation of VPSA oxygen generator is based on mature and reliable technology. It uses zeolite molecular sieve (ZMS) and vacuum regeneration system. The whole process can be divided into three main stages: purification, adsorption and desorption.
1.Purification stage
The first step in oxygen production is to purify the ambient (inlet) air. The air is first filtered to remove impurities and then moderately compressed by the fan system. This pretreatment ensures that the air entering the subsequent stage is clean and meets the requirements of oxygen extraction.
2.Adsorption stage
The pretreated air enters a container containing zeolite. Zeolite is a highly porous material with a unique structure that enables it to selectively adsorb nitrogen molecules while allowing oxygen molecules to pass through. As the air flows through the container, the zeolite further removes residual moisture and carbon dioxide and adsorbs nitrogen, eventually producing oxygen-rich gas that is discharged from the container outlet. Before the adsorption capacity of the zeolite is exhausted, the adsorption process will be interrupted to prevent saturation and ensure continuous and stable operation.
3.Desorption stage
When the zeolite is saturated with nitrogen, it needs to be regenerated to restore its adsorption capacity. The desorption process is achieved by reducing the pressure to below the adsorption pressure. The dry-running vacuum pump generates a vacuum, which releases the nitrogen and other gases adsorbed on the zeolite, and the resulting waste gas is discharged into the atmosphere. To ensure a continuous supply of oxygen, a buffer tank is installed in the system, and the cycle of purification, adsorption and desorption is carried out continuously.
VPSA oxygen generator has many significant advantages, making it the preferred equipment for many industries.
Safety is the primary principle of VPSA oxygen generator construction, operation and maintenance management. Oxygen is a combustion-supporting substance among hazardous chemicals. Fullcryo strictly follows the “GB50030 Oxygen Station Design Specification” to design and build oxygen generators, and installs oxygen concentration analyzers on site to monitor oxygen leakage in real time to ensure stable and safe operation.
Based on the reliability-centered maintenance (RCM) strategy, Fullcryo combines project construction and operation experience to manage the entire process of equipment from installation to production. Through failure mode and effect analysis (FMEA) and historical failure data analysis, preventive and predictive maintenance is carried out on the equipment to ensure high reliability of equipment operation.
Modern VPSA equipment, such as Fullcryo’s products, can be automated through PLC and configuration systems. Under normal circumstances, the equipment does not require active human intervention after startup and is fully capable of supporting unattended operation on site. With the help of remote monitoring software, remote monitoring and operation of the equipment can also be achieved to ensure reliable operation of the equipment. Professional engineers can monitor and diagnose faults on the on-site operating system interface through mobile terminals.
For customers who need a 24-hour uninterrupted oxygen supply, a liquid oxygen backup system is usually configured. The system includes a liquid oxygen storage tank, a vaporizer, and a self-acting regulating valve, which are placed in a suitable location in accordance with safety regulations. Once the main system fails or stops unexpectedly, the self-operated regulating valve will automatically open when it detects that the pressure after the valve is lower than the set value, replacing the main system gas supply to ensure 100% online supply of oxygen.
Fullcryo has a professional product technology R&D team, of which nearly 50% are masters and doctors. Its VPSA process uses LiSX molecular sieve (lithium-based molecular sieve) and is equipped with a vacuum pump for analysis. By calculating the detailed performance data of the molecular sieve, the working flow data of the fan and vacuum pump can be accurately obtained, and then the pipeline and valve specifications can be determined according to the basic design specifications and principles to ensure mature and optimized design.
Some of Fullcryo’s oxygen stations adopt the gas investment model, and Fullcryo is responsible for operation and management. The operating costs include personnel expenses, water, electricity, gas expenses and maintenance costs. The on-site operators usually do not exceed 2 people, and unmanned operation can be achieved at night. Remote intervention can be carried out when necessary, which greatly reduces the overall supply cost.
The energy consumption level depends on factors such as molecular sieve performance, power equipment efficiency, pipeline layout and internal structure of the adsorption tank. Fullcryo uses lithium-based molecular sieves with low silicon-aluminum ratio, which have good nitrogen and oxygen separation characteristics and stable performance for 10 years. The process valve uses API standard valves, which are precise and responsive, meeting the switching speed required by the dual adsorption tank process. The pipeline layout is designed in accordance with the principle of few elbows and short pipelines, with small air flow loss and compact structure. The adsorption tank is a radial adsorption tower designed by Fullcryo, which is filled with molecular sieves, with reasonable air flow distribution and small bed pressure drop.
Fullcryo’s VPSA equipment has a wide load adjustment range, and can achieve 50% – 100% load adjustment through program settings or frequency conversion devices. The VPSA equipment using high-speed magnetic suspension centrifugal fans has a wider adjustment range of 20% – 100%, which is significantly better than the 50% – 100% adjustment range of conventional domestic VPSA equipment, and can flexibly adapt to different gas needs of customers.
Fullcryo’s VPSA team is experienced in the design, construction and operation and maintenance of oxygen production stations. After the project started, from the initial process design to the final completion and commissioning, the team engineers were deeply involved in all aspects, including the design and construction of civil engineering that may be responsible for the customer, and were able to carry out targeted design according to customer needs and on-site oxygen conditions, and provide professional solutions.
The VPSA equipment consists of a fan module, an adsorption tank module, an oxygen compression module, an exhaust muffler module, etc. Fullcryo adopts a skid-mounted design, which concentrates each module on the skid body, further reducing the volume and achieving a compact layout.
Fullcryo’s professional engineering project team covers multiple fields such as process design, equipment, electrical control, instrument control, safety, quality, and procurement. In the engineering design stage, three-dimensional design is used to optimize all installation processes. Small equipment molding pipelines, heat exchangers, fans, etc. are assembled on skids, and all compressors are skid-mounted and shipped. Large equipment is prefabricated and assembled on site, and some non-pressure pipelines and normal pressure pipelines are connected flexibly, which greatly shortens the construction time and reduces the workload of on-site installation.
Using the principle that sound waves reflect and interfere and weaken in a specific structural cavity due to sudden changes in the flow channel cross section, Fullcryo has simulated and experimented with different cavity structures many times to obtain sufficient data. The multi-cavity concrete exhaust silencer designed can effectively prevent low-frequency exhaust noise from spreading over long distances and create a quiet operating environment.
VPSA oxygen concentrators are widely used in many industries.
In stainless steel production, argon oxygen decarburization (AOD) furnaces use oxygen to blow into molten steel to remove excess carbon and reduce the burning of precious elements such as chromium. Oxygen directly participates in chemical reactions such as high-temperature smelting, decarburization, and dephosphorization, which can accelerate the decarburization reaction rate and improve production efficiency; increase the temperature of molten steel, which helps control the quality of finished products; reduce energy consumption in the metallurgical process and reduce the use of expensive alloy materials. The use of VPSA oxygen generators for on-site oxygen production has flexible supply and rapid response, reducing the cost of raw material transportation and storage. 80% – 94% purity can meet the metallurgical decarburization needs, without the need to pursue ultra-high purity.
VPSA oxygen generators are used in glass kilns, cement rotary kilns, papermaking drying furnaces, ceramic sintering furnaces, metal heat treatment furnaces and other fields. Introducing oxygen-enriched air into the combustion system can improve fuel combustion efficiency, increase combustion temperature, and accelerate complete combustion of fuel; reduce energy consumption, reduce fuel consumption under the same energy output; reduce emissions of pollutants such as nitrogen oxides, carbon monoxide and dust, and help enterprises meet environmental emission standards. The VPSA system can adjust the oxygen production according to the gas load, which is energy-saving and efficient, and is particularly suitable for industrial furnaces with continuous and periodic gas consumption.
VPSA oxygen generators are used to treat pollutants in industrial waste gas (such as coking waste gas, chemical tail gas, and power plant waste gas), as well as environmental protection processes such as desulfurization (removal of sulfur dioxide) and denitrification (removal of nitrogen oxides). Oxygen plays a role in strengthening the oxidation reaction, accelerating the reaction speed and efficiency, such as oxidizing sulfur dioxide to sulfur trioxide, which is easy to be captured by the absorbent; assisting the catalyst reaction, providing the necessary oxygen environment in selective catalytic reduction denitrification (SCR), and improving the removal efficiency; promoting the microbial treatment process, such as in biological desulfurization, providing oxygen for sulfur-oxidizing bacteria and enhancing their activity. Setting up a VPSA oxygen generator nearby as an oxygen source avoids the transportation of bottled or liquid oxygen, which is low-cost and suitable for large-scale, continuous oxygen supply environmental protection projects.
Fullcryo has accumulated rich experience in the field of VPSA oxygen generation technology and successfully delivered many typical projects. We built two 1100Nm³/h, 93% purity VPSA oxygen generators for Jiangxi Rijia Copper Industry, optimized the combustion system, and significantly saved fuel costs; provided 2×7500Nm³/h, 80% purity VPSA equipment for Henan Anyang Iron and Steel through the EPC general contracting model, improving the customer’s oxygen supply redundancy and reducing oxygen production costs; built a 6000Nm³/h, 90% purity VPSA unit for Huagan Ruilin to support the green development of the renewable resources industry; customized a 1500Nm³/h low-noise VPSA gas supply system for Taichung customers to meet the needs of small space deployment, fully demonstrating flexible and efficient engineering capabilities.
